The Alchemist
by BlueNeutrino
Summary: Final part of The Physician series. The surgery failed. Dean is dead. But as they should have learned by now, the Mark of Cain isn't done with him yet.
1. Prelude

**A/N: Welcome to the final installment! Warnings for gore, violence, and some of the twisted turns the story takes towards the end. I initially didn't intend to write the story in three parts and Dean was gonna be fine at the end of** ** _The Surgeon,_** **but bringing back demon!Dean was just too good an opportunity to pass up.**

A grin spreads across Dean's face as the Impala rolls to a stop at the end of a long, winding driveway. It widens further as he and Sam step out, gazing up at the towering form of the decrepit manor in front of them. "Now that, Sammy, is what you call the real deal," Dean remarks. "When was the last time we checked out a haunted house that looked like that?"

"Alright, don't jump the gun," Sam gently chides as he goes to fetch the EMF meter. "We aren't even sure there's a case here yet. Let's just scope things out first."

He takes the EMF meter from the car and lightly flicks the antenna as he turns it on, the machine giving no response. Undeterred, Dean goes to fetch a couple shotguns and salt rounds from the trunk. "Yeah. But just to be on the safe side." He tosses one to Sam before the pair of them make their way towards the gothic doorway at the top of the porch.

It's open, apparently, as Sam gives it a push. The minute they cross the threshold, the EMF meter springs to life, whirring and bleeping in Sam's hand. Dean gives him a look. "Told ya, Sammy."

Their footsteps are loud on the marble floor as they cross the lobby, leaving traces in the dust that's turned the glossy stone to white. Cobwebs hang thick from every possible surface, clinging to the banister of the grand staircase and hanging down from the crystal chandelier overhead. Dean lets out a soft whistle. "You feel like we've just stepped onto the set of a horror movie? This hardly seems real."

"Yeah, I know. It's like it ticks every cliché in the book," Sam agrees as he lingers just below the canvas portrait of a stern looking Victorian woman in a gilt frame. The EMF meter grows even more excited.

"Alright, so where are the ghosts?" Dean says, eager to cut to the chase. He loads up the first shell of rock salt into the shotgun.

As if on cue, a sudden breeze blows past them accompanied by a creaking noise, and both boys look up to the first floor landing where they see a door has just swung open.

"It's that way," Sam declares, and Dean's almost surprised by how he says it in such a tone of absolute certainty.

"You sure you don't want to check out more down here first? EMF seems to like that painting," Dean says as Sam strides past him and begins ascending the staircase, but that suggestion goes ignored. Dean blinks, surprised for a moment that his brother doesn't so much as look at him, but then shrugs it off. He steps forward to join Sam on the stairs.

The moment his foot lands on the faded red runner, a sudden jolt of pain of pain sears through Dean's chest. He gasps, frantically clutching at the handrail as his head begins to spin. White flashes all around him and he hears voices in the distance, " _What if he wakes up…?"_

He can't breathe. Something's lodged in his throat and he's choking on it. His chest is burning and Dean thinks he's just about ready to pass out…

Then it's gone.

He gasps, eyes darting frantically about him as he wonders what the hell that was. A glance down at his own body tells him he's fine. "Sam!"

His brother doesn't seem to have noticed his episode. In fact, Sam doesn't seem to be paying him any attention as Dean looks up to see he's already reached the landing. Without so much as a backward glance, Sam vanishes through the doorway.

Alright. That's definitely weird.

"Thanks for waiting," Dean grumbles, rubbing at his chest as he ascends the stairs. If this is a haunting, it's not the first time they've experienced something like that: echoes or visions brought on by whatever spirit is in this place. Still, it's unsettling.

Dean paces the last few steps and then turns to enter the room. "Alright, Sammy, what you…" The question fades to silence as his final turn reveals that the room is empty. And by empty, he means _empty._ It's entirely devoid of furniture, the floor comprising boards of plain dark wood with more than a few scratches and chips in the varnish. The faded wallpaper has been partially stripped from the walls, leaving behind peeling chunks of dull floral pattern. Cracks show up stark in the plain ceiling plaster, a cable hanging down from a hole in the center showing where a light fitting would once have gone. In one wall there sits a barren stone fireplace, with just a few grimy remnants of charcoal and soot left behind in the grate while a rusted, redundant poker lies off to one side. Another chilling breeze blows down from the chimney, and Dean gives an involuntary shiver.

There's no other apparent exit save for the windows, and Sam is most definitely not here.

Dean blinks, for a moment wondering if he's somehow entered the wrong room. No, this is definitely the one where the door had opened of its own accord, and he'd seen Sam enter through that exact same door. He takes a few paces forward, the unease in his stomach growing as he looks to see if there's perhaps another exit he'd missed. The only source of light in the room is the windows, and Dean crosses to them, pulling open the weathered shutters wider to stare out at the space beyond.

He can see nothing. Where he'd been expecting to see gardens or grounds at the back of the house, all there seems to be is mist: a thick white sheet of it that blends seamlessly into the dull grey sky. That definitely hadn't been here when they arrived.

Fear is just beginning to overtake his confusion when a dull throb of pain pangs behind Dean's sternum again. He grimaces, a hand going up to rub at his chest as he tries to make sense of this. Sam can't have just vanished…

Turning away from the windows suddenly brings it into focus: there, in the wall to the left of the fireplace, is a door. It's the most vibrant thing in the desolate room, painted a vivid red as if beckoning him to open it, but the sight makes Dean's blood run cold. No way was he so unobservant as to simply not notice it before.

 _So, did Sam go that way?_

A door that vanishes and reappears on a whim. Not exactly run-of-the-mill, even for him, but, well, the house _is_ haunted. Dean raises the shotgun and reaches for the handle.

It turns with a soft click, and Dean holds his breath as he takes a cautious step beyond the threshold. The room on the other side is dark. This time there are no windows, and it puzzles him for a moment as he realises the shape isn't at all consistent with how he'd assumed the layout of the manor to be. It seems more like a hallway than a room, with dim, yellow lights spaced at regular intervals along the walls, fading to darkness in the distance. Dean takes another step forward, hearing the soft click of the door closing behind him. The noise sets him on edge and he glances back nervously, only to find that the door he'd entered by has vanished. Now there's only solid wall.

"Alright, this is some Inception level shit," he mutters, turning back to stare down the corridor again. By now, he'd be expecting to hear his pulse thumping in his ears, but it's strangely quiet. Well, plus one for keeping calm, he guesses.

He begins to walk, keeping a firm grip on the handle of the shotgun until a flickering light on his left brings something into view. There's something written on the wall.

Dean turns, feeling a chill as he takes in the words, and the dark, glossy substance in which they're written.

 _You're dying._

His blood turns cold. Really, he's sure his heart should be pounding by now, and the fact he can't feel it only makes things worse. He reaches out a tentative hand to check whether that's _really_ written in what he thinks it is…

As his skin makes contact, the world suddenly flashes white again. He gasps, feeling a familiar rush of pain as he collapses to his knees and fire tears through his chest. There's a roaring in his ears, a voice shouting his name…

 _"Dean!"_

He knows that voice. Knows it's Sam. But where is he…?

A heartbeat later, and again it stops.

Dean drags an agonized breath into his lungs, panting as he waits for his head to stop spinning. He's only half lucid again by the time he realises he's not where he was before.

The floor is again wooden boards, he'd guess from the smell of old varnish before he even lifts his head to look. When he does, it seems that the new room is brighter than before. Again, there are windows in one end giving a view of plain white mist, and from the rafters in the ceiling, he'd guess he's in some kind of loft. Picking himself up, Dean finds himself staring at the grand feature of the mostly empty room: a grandfather clock standing isolated in the middle of the floor.

It isn't ticking. The silence of it is almost deafening as he stares at the static pendulum through the glass case. A voice in the back of his mind is telling him to leave, to go find Sam, figure out what this place is, yet it's nothing more than a quiet whisper. Something else is drawing him closer.

The shotgun remains abandoned on the floor as he steps forward and raises a tentative hand to touch the clock face, frozen in place at 3:27. Looking around, he can see there are wires – _so many wires_ – seeming to run into and out of the back of the clock, and if confuses him because _grandfather clocks don't run on electricity._ He doesn't look to see where the wires lead. It doesn't seem important. What matters is that the clock needs fixing. And it's urgent. It needs fixing _now._

Dean doesn't even ask himself why.

With the utmost care, he unlatches the door to expose the inner gears and mechanisms of the clock. He doesn't understand them. Doesn't pretend to, yet still he reaches in amongst all the cogs and gears that seem to have come askew and need putting back into place.

 _Why am I doing this?_

The question briefly occurs to him, but it's too hard to answer. He lifts up the broken parts, tries to piece them back together, and is surprised to find that suddenly there's blood coating his hands. He pulls back, wondering if he's cut himself without realising, but then it dawns on him that he's not the one bleeding. It's the clock.

That should seem strange, but it doesn't. It just makes him more desperate as he reaches back in and tries to stop it, tries to fix everything, but everything's in pieces…

He's vaguely aware of the rushing in his ears, the whirring sound from somewhere nearby, the flickering of the lights _even though the only light is coming from the windows…_ But none of it hits home until a loud crackling cuts through the air and he's suddenly knocked back from the clock as a surge of electricity courses through him.

Dean hits the ground, winded, and suddenly he's thinking straight again. His chest hurts, but he blinks and shakes his head, wondering what the hell is going on. A glance down at his hands, and he realises they're clean. There's no blood. None of this makes any sense…

" _Dean!"_

Through the confusion and fear, a voice hits his ears again. It's the same as earlier except, if anything, more urgent, and Dean remembers. He needs to find his brother.

"Sammy!" He forgets about the clock, whatever it is, and snatches up the shotgun again. Where did Sam go? If this places manages to keep screwing with him and teleporting him all over the place, he could be anywhere.

Dean glances round, looking for an exit, and another chill courses through him as he sees words written on the wall above a staircase leading down. _Can you find me?_

"Yeah, I'll find you," he growls as he crosses to it, all caution abandoned as he begins to hurry down the stairs.

It takes longer than it perhaps should for him to realise, _Wait, this isn't even the house anymore. It's the entrance to the bunker._

He's given up trying to make sense of it. Instead he just runs, making his way through the now-familiar hallways as the lights once again flicker and he hears Sam's voice cry out his name. Breathing is painful and he thinks the front of his shirt is starting to feel damp, but he pays it no attention. His mouth goes dry as he sees the trail of blood on the floor and begins to follow it, boots pounding into the ground in a way his heart still _isn't._

Panic is setting in as he sees the next message scrawled in blood on the wall – _You can't hide from me_ – and then he turns a corner. _That_ corner. The one where he…

He doesn't finish that thought as his eyes fall on the body crumpled at the end of the hallway. "Sam!"

Terror has overtaken him as he rushes to his brother's side, praying it isn't as bad as it looks. He can see the huge chunk that's been taken out of the side of Sam's head, the brain matter that's spattered onto the wall…

 _Nonono…_

It's useless as he reaches his brother's body and kneels down beside it, trying to cradle Sam's head but only causing more red pulp to spill out. "No, Sammy, I'm sorry…"

Everything's suddenly becoming clear, and it feels like a million knives sinking into Dean's cold, unbeating heart. Tears mist over his eyes as all he can think to do is pull his brother's body closer to him and cradle it, rocking Sam gently as the guilt crashes over him. He knows what's happening. It's his worst fears coming true, yet it's still a sickening surprise when he hears a familiar voice behind him.

"He's not waking up."

Dean turns his head to stare into a face: his own face, but instead of green all he sees are cold black eyes. Blood drips off the hammer clutched in the demon's – _his own –_ hand.

His demon self sees the look on Dean's face and chuckles. "And neither are you. But I think you knew that."

Dean swallows, almost overcome by the fear flooding his veins, but he manages a defiant glare as he sets Sam gently down. "None of this is real." It's sounds more uncertain than he'd hoped.

The demon gives a shrug. "It's real in every way that matters. I did try to warn you, Dean. You're dying. Well, _dead_ now, I think. You're not opening your eyes again. Me, on the other hand…"

Shakily, Dean grasps the shotgun and rises to his feet. "No. I won't let you – I won't _be you_ again."

He's met with a cold, threatening stare. "You think you have a choice?" The demon glances down at the bloody hammer still gripped in its hand, and steps forward.

Dean glares back. "Damn right I do." He raises the shotgun and fires.

Rocksalt sprays out, hitting his demon self in the chest, but he barely flinches. "Your heart's already in pieces. You're gonna have to do better than that."

There's another rush of pain and Dean gasps, a hand clutching at his chest once again. It comes away coated in blood.

He's unsteady on his feet, but he manages one final display of defiance as he snaps another round into the chamber and fires again. The demon laughs and raises the hammer. "Better start running, Dean."

This may only be a nightmare, but suddenly it's all too real. Dean knows he doesn't have a choice. He turns and runs.


	2. I

_He's gone._

Cas stands at the side of the bed looking down at Dean's face. He feels numb. Unreal, almost, like what he's just witnessed didn't actually happen. If only he'd had better judgment, it wouldn't have. They should never have let Dean do this-it was too much of a risk. Cas knew it. Sam knew it. If only he'd put his foot down harder…

Too late for that, now.

There's still tape over one of Dean's eyes, a tube down his throat, looking cruel and obscene now that there's no function for it to perform. Tentatively, Cas reaches out to remove the tape and slides the intubation tube away. If nothing else, this should be peaceful.

The surgical sheets are crumpled and stained red. It's a savage scene, more easily mistaken for a massacre than a surgery, and Castiel feels a lump forming in his throat as he resists the urge to tear them away. Clothes. Dean should have his clothes first. The angel smooths down the sheets as best he can then turns to Dean's chest, wanting to clean up some of that mess. He should be whole in death. Dignified. Castiel reaches out to remove the clamps and the rib spreader and all the equipment Carter's just abandoned, forcing himself not to get angry for Dean's sake. There'll be time for that later. He can already hear Sam yelling indistinctly down the hall, and at least one of them has to keep it together.

A fleck of blood is clinging to Dean's lips, and Cas tenderly reaches out with his thumb to wipe it away. He lets his hand linger, brushing back Dean's hair from his face, fingers trailing down over his cheek. His other hand reaches for Dean's, then pauses abruptly, a frown creasing on Cas' face as he realises something's wrong. He pushes back the coverings then looks down, the frown turning pissed as he sees the restraints around Dean's wrists. What are they doing here? That's not right.

Castiel reaches out and undoes the straps.

* * *

" _There's no point, Sam. He's dead."_

Sam's fists clench and unclench at his sides, mind racing, refusing to let the words sink in. "You said he wouldn't die," he says, voice strained against the lump in his throat. "You promised."

Carter scowls, busies herself with pouring another glass of whisky then takes a gulp. "When was that?"

Sam fucking snaps. He grabs something from the side-beakers, bottles, he doesn't even know what-and swipes the contents of her kitchen counter to the floor. Glass shatters loudly. She doesn't flinch, but he sees her eyes widen. "How the fuck can you just stand there, _drinking?_ " he roars. "You let my brother die and you don't even seem to care. It was your job to _fix_ him. He didn't convince me and Cas to come all the way out here and bring you ten grand in a duffle bag for this."

There's a pause in which Carter downs the rest of the drink then slams the empty tumbler onto the countertop with a glare. "Well, I didn't exactly advertise for a bunch of demons to come and gatecrash now, did I?"

Sam glares. He wants to punch her, then a better thought occurs to him. "Fine," he growls, then turns and begins to stride away. He hears her call after him.

"Sam?"

"There's three dead bodies in there. If you've fucked up my brother's heart, you can damn well make a transplant out of one of them," he spits, walking with renewed purpose as he heads off in search of the dead demons.

Carter catches up fast. "Whoa, hey. Sam!" He feels her death grip close around his upper arm, spinning him round to face her. "You think I can just make a transplant out of anything I please? No immunosuppressants. Not even checking for a match. You'd just be fucking your brother over more."

"How exactly can he be more fucked over than _dead_?"

"Look, Sam," she says tersely. "Your brother has the fucking Mark of Cain branded into his arm. Last time he died, he told me he came back as a demon, and that's the whole reason we're here. So, if you don't mind, I'm going to wait for that to happen. _Then_ we'll see where we go next."

Sam stares at her, chest heaving, then his shoulders slump. Maybe she's right. He almost doesn't want her to be. "Do you have any idea what I went through to cure him of being a demon?"

"I know a thing or two about demons," she says, and it seems to him that some of her confidence has returned. "Trust me."

Sam sighs. That's a big ask. He lets the final waves of rampaging anger crash over him, then draws a deep breath and drags a hand over his eyes. When he's done, he feels calmer. "How long will we have to wait?"

"You'd know that better than me."

"Shouldn't you at least…" He struggles to say it. "Close him up?"

A beat. Then Carter nods. "Alright. Yes. You're right." She steps back into the kitchen to take a final shot of whisky, then walks past him back in the direction of the surgery room without even a glance. Sam follows.

Cas is still standing by Dean's body when they get there. He looks up when they enter the room, but other than that doesn't react. Sam thinks his eyes look red.

The monitors are off, equipment removed, Dean's chest covered with fresh paper sheets. He's cleaned up.

Carter scowls. "Who said you could touch my stuff?"

Cas ignores that, instead looking past her to Sam. "I'm so sorry." His voice is rough. Pained.

Sam shakes his head. "Not your fault, Cas." He doesn't try to disguise the pointed glare he shoots at Carter's back.

She strides over to Dean and reaches up to pull open his eyelid, indifferent to the care Cas has taken in closing them. There's a couple of seconds in which she studies it before letting go again and pulling back the drapes from his chest. "You couldn't have just left him be?" she snaps in irritation as she sees Cas has removed the spreader.

Sam sees the angel's fists clench. "He's my friend. I was hardly going to leave him like that."

"Yeah, well. Now it's just even more trouble to fix. I was gonna close up his pericardium." She gives a huff, turning to search for the rib spreader again, then decides she can't be bothered. "Oh, what the hell. He'll be fine without it."

"In what way will he be 'fine'?" Cas growls, and she rounds on him with a glare that's equally pissed.

"Well, he did keep telling me that if he died, he'd come back as a demon. Or have I completely got the wrong end of the stick?"

Cas' eyes narrow. "If that's the eventuality you're preparing for, what do you plan to do with him?"

"Just get me the staple gun. I'm going to put his sternum back together, if that's alright with you, Mr Angel-of-the-Lord."

He returns the fierce glare with a wary look before glancing at the equipment table, deciding that her plan doesn't seem to be a bad one. Cas takes the staple gun and thrusts it at her. "Here."

She gives a sardonic smile. "You're actually not a bad assistant when you stop questioning me."

Carter turns back to Dean, businesslike again as she pushes back his skin and inserts some fresh packing to work on his ribcage. Sam's still struggling to look, having to turn away when he sees the white of bone again. He misses the flutter in Dean's eyelids.

So does Carter. "Alrighty then," she says, hefting the gun into position as she realigns his ribcage. "Let's do this."

The end of the gun begins to lower, settling into place for the first staple as Carter prepares to pull the trigger. Before she can, a hand suddenly darts up to close tight around her wrist. "Not so fast there, Doc."

It's not often that things startle her, but Carter's eyes widen in shock. Her gaze flies to Dean's face to see black eyes fixed menacingly on her and his lips pulled upwards in a smile.

* * *

Dean's chest is on fire. He can barely breathe, can't even see as his vision swims in and out with red, but it's all he can do to keep running. There's no other escape. No way to fight it off.

He glances back again at the ever-present figure on his tail, never more than a few steps behind as he offloads another round of rock salt. It doesn't stop. The demon continues to advance, nothing more than a walking pace while Dean himself continues to run, and he doesn't even question how it makes sense.

Blood drips from his chest. He stumbles, struggles to keep going as the image of a dead Sammy seeping brain matter onto the concrete floor invades his mind. He doesn't even know where he is anymore. It doesn't matter. The world inside his head has lost all structure, fading to nothing but darkness and shadows through which he runs as his demon self tirelessly pursues. He can't stop.

He doesn't know how much longer he can keep going.

"You can't run forever, Dean," his own voice taunts, and Dean feels like he chokes on the words. Each footstep thunders in his head, like a taunting reminder of the heartbeat he no longer has, and he isn't sure what kind of floor he's running on. The only thing beneath his feet is black.

"Just give in to it," a voice says, this time right by his ear. "It's better this way."

In the distance, he hears a clock chiming. He's run out of time.

Spent, Dean falls to his knees, gasping for breath as he stares down at the gaping hole in his chest. He blinks, and as his vision clears, he realises this time he's back in the clock room again. The floor is soaked in red.

In front of him, the grandfather clock stands, hands no longer fixed on his time of death as it chimes twelve. The sound rings in his head, and through it he hears footsteps, heavy boots on the blood-drenched floor steadily approaching.

He looks up to see black eyes staring down at him, a hammer hefted in his hand. "It's over, Dean," he says.

The clock chimes ten. The hammer draws back.

 _Eleven._ Dean's arm swings.

 _Twelve._

His skull shatters and his human self knows no more.


	3. II

**Warnings: Gore. While there has been plenty of that in the series so far, this chapter may get a bit much for some readers.**

"This operation is over." Dean's voice drops low, the black in his eyes clearing, but the look of menace in them remains.

Carter tries to pull her hand away. "Why do you think I'm trying to staple you up?" He halts her, his grip closed tight around her forearm, and she turns to shoot a glare at Cas. "Fucking idiot." The angel at least seems to realise his mistake.

He looks on in a combination of shock and horror as Dean begins to sit up, blood spilling from the opening in his chest, and Carter swiftly raises her other hand to grab the gun. Then, she jabs it towards Dean's face and pulls the trigger.

It happens too fast for him to react. The staple buries itself in the soft flesh beneath his eye and he hisses, lips curling into a snarl as he wrenches her closer towards him then viciously backhands her across the cheek. She grunts, stumbling away as she collides with the equipment tray and the gun falls from her hands, but she's got him to let go.

Dean's legs swing over the side of the bed, then, surprisingly steady, he stands. He lifts a hand to pick at the sliver of metal in his cheek, examining it with a scowl before tossing the staple like nothing more than an annoying piece of lint. His eyes settle on Cas, then pan to Sam, a twisted leer on his face. "What's wrong, fellas?" It's a cruel mockery of his first words to them, after last time. "You look worried."

It's like a scene from a horror movie, _Frankenstein_ meets _ReAnimator_ in full technicolor gory, and Sam's rooted to the spot. There are still tubes stuck into Dean's arms, crimson pouring from the gaping hole in his chest while the jut of his ribs frames the opening in obscene chalk white. The hospital gown hangs loose and bloody from his hips. All Sam can do is stare, barely able to feel the ground beneath his feet as he wonders if this is really happening.

Cas reacts faster. He steps forward, expression grim as he raises his hand with two fingers extended, and Dean gives him a bored look as the touch lands on his forehead. "Sorry, Cas. Not this time."

There's barely a second for Cas to realise it isn't working before Dean grabs him by the throat, then throws him hard across the room. He hits the far wall then falls to the floor with an "oof" before going still.

Dean looks unimpressed. "Angel without his grace. What use even are you?" he remarks as he shoots Cas' limp form a derisive glance, then turns his attention to his own body as he starts pulling away the remaining wires and tubes stuck into him. More blood drips to the floor.

Meanwhile, Carter's cautiously watching. She snatches a glance at Sam, who seems to be frozen in shock, then her hand pans over the equipment table and curls around the handle of a scalpel. "Dean."

Disinterestedly, he looks up, and smirks when he sees the tiny instrument pointed at him. "Yeah. Real scary."

"Sharp enough to cut hamstrings, then I promise you aren't going anywhere," Carter says coldly. "I've spent long enough fixing you today. Don't make me do more damage."

"Sweetheart, I'm not _making_ you do anything." He scoffs, then rips out his catheter to a fresh rush of blood. It doesn't seem to bother him. "But hey, if you want to go for round two, let's try it."

He takes a pace towards her, but Carter holds her ground. "I've beaten you once."

"Yeah, but you had a lot more gas that time." He gives her a mocking leer. "How's that working out for you?" He takes another step then picks up the pace, barreling straight towards her with his open chest front on.

Sam watches, desperately trying to force his mind into gear as he realises _this is real - you need to do something_. He sees Carter actively pull back, twisting out of the way to avoid doing damage to his exposed organs, then she sidesteps and aims, as promised, for the back of his legs.

Dean's too fast. He effortlessly steps out of reach, leaning forward in a way that makes his organs bulge out from the hole, and Sam feels his stomach turn in anxiety and disgust.

The demon glances back at Carter and smirks. "Seems like you've lost your touch."

Silently, she glares. Her jaw clenches and she twirls the scalpel twice between her fingers before going again, rushing him at a pace the human Dean would never have had chance of avoiding.

Demon Dean, on the other hand, just seems amused. She's going for a sideswipe, but instead of stepping out of the way, he leans into her path, forcing her to redirect to avoid colliding with his vulnerable chest. He does it twice before Carter nimbly switches hands and steps wide around him, swinging her hand back to slice at the underside of his knees.

This time, she draws blood before he stops playing long enough to leap away, rounding back on her with a glare. He's pissed, but it's barely even caused a limp.

Carter keeps her distance, nervously eyeing his chest. There's no way to keep this up without his lungs or heart or something at some point to come spilling out, and he knows it.

Dean grins. "Third time lucky. One more try?" Carter doesn't move. "Yeah, thought not."

He doesn't even give Cas or Sam a glance as he turns and strides for the exit, knowing she won't try to stop him. He's practically at the door when Sam finally finds his voice. "Dean. Stop."

The only reaction it gets is a raised eyebrow as Sam moves, legs on autopilot as he come to stand directly in front of Dean, blocking his brother's exit. He swallows thickly around the lump in his throat. "I'm not letting you leave."

Dean gives him a hard stare. "Get out of my way, Sammy."

"No." Sam grits his teeth, forces his voice to be strong. "We brought you here to cure you, and that's happening whether you like it or not."

Black flashes once again across Dean's eyes. " _Move_ ," he growls, voice low and deadly. "Or I'm going to start picking up power tools."

Sam stands his ground, stares into the black pits that once used to be a warm, familiar, green. He's not letting his brother disappear again. "Then do it."

Dean hesitates. It's not for long, just the briefest second as his eyes fade to normal again, and for a moment Sam thinks he can still see his brother there. Then, Dean raises his hand and slides it between his own cracked ribs.

"You want me to stay?" the demon says, curling his fingers around the red mass of his heart. "Fine. But you don't get me whole." He begins to squeeze, straining the stitches Carter's meticulously put in place as he starts to tug. "Get out of my way, or this comes out."

Sam swears he feels his own heart stop. "Oh god, Dean. Don't," he chokes out, fear and nausea competing to strangle his voice into nothing. "Don't do that. Please. Don't."

Dean doesn't back down. His fist closes tighter, eyes hard. "Your call, Sammy."

Sam's trembling. For a moment he's torn, wondering if he should just step aside and mitigate the damage even if it means losing Dean again for god knows how long, but there's part of him still clinging onto a far-fetched hope he can fix this. What if he tackles him, pins Dean's hands to stop him harming himself? Perhaps he could manage it—they're standing close enough, Sam just has to be fast...

He isn't fast. His indecision drags out, and it keeps Dean waiting a second too long.

There's no way to know if he's not actually prepared to follow through on the threat, or maybe he's just growing impatient to get away, but with a look of irritation Dean lets his hand slide harmlessly out of his chest again with a horrible squelch. At the same time, he raises his other hand and gives a sideways flick of his wrist.

Sam feels the familiar tug of a supernatural force around his spine, then he's being flung through the air, knocking over the tripod with camera still in place before he collides with the wall and drops down roughly next to Cas. So that's a power Dean has now. It looks like dying for a second time has brought him back even stronger.

Beside Sam, Cas has started to stir, lifting his head just enough to stare in horror towards Dean. The demon turns and fixes them both with a look of contempt, pure hatred pouring out in his gaze as it looks for a moment like he wants to kill them both. Then, he turns away and strides out of the door without a backward glance.

Panic begins to swirl in the pit of Sam's stomach. He glances over at Carter, still standing immobile several meters away, and out in the hallway he hears the sound of receding footsteps followed by crashing as Dean decides to wreck even more of the place on the way to the door.

He's not losing his brother again. Not like this. He can't.

Sam scrambles to his feet, one step ahead of Cas on the way to the exit as he's determined to keep his brother from vanishing even if he still has no idea how, then he feels a tight grip close around his shoulder to hold him back.

His head whips round, anger and fear and desperation all pouring out in the look he shoots Carter as he sees her standing with one hand each on him and Cas. "Wait," she says, voice quiet.

Sam struggles as he tries to shrug her off. "It took me five months to find him last time. Let me go. I'm not letting him vanish again."

Her grip only tightens as she makes a shushing noise, telling him to be quiet. "I said wait."

In the distance, he hears the unmistakable sound of the Impala's engine revving from the parking lot. Panic swells in his chest. "Why the…"

"Didn't you notice?" she suddenly cuts him off, and he's too overwhelmed and confused and outright panicked to even articulate the rest of the sentence.

Carter finally lets go as she looks from him to Cas. "The cut on his face," she says calmly. "It's already closed up. He's healing."


	4. III

Sam blinks. Once, twice, then it finally sinks in. "Wait, you mean…?"

"Yes." Carter states it with confidence. "24 hours, at most, and his heart and chest will be fixed. So let's not provoke him. If he decides to rip it out because he's being followed, that's a lot harder to come back from."

Sam's still processing, trying to figure out what to make of it. Cas narrows his eyes. "The fact still remains that as of now, Dean is once again a demon. And missing. Last time he managed to evade us for months, and that _isn't_ what we came to you for."

A defensive scowl settles on Carter's face as she gives a dismissive roll of her eyes. "Relax, feathers. Him being a demon is _exactly_ what's going to make him easier to find."

They both blink at her once again in confusion, but she's already striding back out into the hallway. There's a sense of purpose to her step as she ignores them both, heading back in the direction of the kitchen while Sam and Cas make the quick decision to follow. They exchange a glance, and for a moment it's clear Sam is still considering going after Dean. Then in the distance, there comes the unmistakable sound of the revving engine of a 1967 Impala.

Sam's eyes fly wide, panicked. "Shit," he murmurs, looking even more like he wants to bolt for the parking lot.

"I said we'll find him," Carter says tersely without even glancing at him, stepping over the debris on the floor to throw open several cupboards. She begins to gather several items, chemicals and powders and herbs, and amasses them on the central island counter.

Cas watches in agitated curiosity as she sets down a pestle and mortar. "How?"

"Business cards," Carter says without breaking her stride, and that causes both of them to blink.

"Excuse me?"

"You think I get my business just by word of mouth? I move cities every few months," Carter says, pulling open a drawer and taking out what appears to be a cheap, fold-out tourist map of Chicago. From what Sam can glimpse inside the drawer, she has several. "Each new place, I do a quick spell that finds the approximate location of any relevant parties in the area, usually demons, so I can send out business cards." She opens the map and spreads it across the countertop before turning her attention to the mortar.

Sam raises an eyebrow. "You have business cards?"

She looks up, disgruntled, then reaches a hand behind her to pull open a second drawer. She snatches a few white, rectangular cards from the top of a pile and flings them at him. "Here."

A couple of them land on the floor. A few on the counter top. Sam bites his tongue and picks one up.

It's plain and unembellished: an unfussy sans serif font across a few lines.

 _Dr. Carter_

 _Demon physician and alchemist_

Followed by a phone number and a two line address. Sam frowns at it. "What is it you even do? It doesn't say."

Carter shrugs, not looking up from the mixture she's currently grinding into a paste. "No, but one of those mysteriously appears in their back pocket, a lot of demons are curious enough to find out."

That only raises more questions. Ones that Sam doesn't have time for. "And how does this help Dean?" he asks instead. "We find him, and then what?"

"You're the expert on that. You've cured him before. You tell me." She adds something to the concoction and a pale, yellowish gas begins to drift up from the mortar with a hiss. The smell is acrid and bitter.

Sam wrinkles his nose. "It needs a ritual. Purified blood."

"I'm an alchemist. I think I know a purification procedure or two."

"And the blood?"

She pauses, looks up at him. "Well, you have eight pints."

That's at least one way they're on the same page, then.

Carter snatches up a handful of powder and drops it into the mix, causing the whole thing to sizzle before sparking with a bang.

Cas squints at the smoke trail it leaves behind. "So this is alchemy?"

Carter pulls a face. "No," she sneers. "This is witchcraft. Alchemy is a lot harder."

The concoction sizzles again. Carter takes that as her cue to add another ingredient. Sam looks down at the map. "You said it can trace all demons in an area. So, what? We're meant to go through all of them one by one? I'm not seeing how that helps."

"You want to find demons, you add sulfur," she says, emphasising that by adding a pinch of the yellow powder. "You want to find something more specific, well, you have to be a little more specific. Add something unique."

Sam swallows. "Like blood."

Her silence confirms it. There's enough of that left in the operating room, probably still clinging to the tubes of the bypass machine. It's enough to make Sam's stomach turn, but he knows what needs to be done. "I'll go get it."

He's about to leave, but Carter cuts him off. "No need."

Sam glances back, a questioning eyebrow raised.

She at least looks a little sheepish as she turns away and heads to the fridge, allowing Sam to see the rack of test tubes kept on a shelf before she selects one and brings it over. Sam can see the deep crimson liquid inside, and just about make out the text on the handwritten sticky label reading ' _D. Winchester_.' "Got that covered," Carter says, opening the vial and allowing a few drops to spill into the mortar.

It immediately leaves a sour taste in Sam's mouth. "Why do you have my brother's blood?"

"First time he came here, I ran a blood test."

"Does he know you have it?"

"Of course he does," she snaps, then hesitates. "Well, he sure knew I took it. Didn't tell him I kept it, but I thought that went without saying."

She picks up a spatula from the side and gives the mixture a final stir, then ladles out a small blob of thick black goop that she allows to drip onto the map. It takes Sam a second to realise it's over her address.

"Alright, here we go," Carter says as she takes a box of matches from one of the drawers. She strikes one and holds it over the globule of viscous black fluid. " _Igne, in quo mihi_." The flame touches the substance.

There's another brief flash, a tiny white spark where the match makes contact, then Carter steps back. The black goo starts to glow, a hot orange-red like molten rock as it slowly begins to creep across the map. Tendrils of black spread out from the central point. It takes a few seconds for one of them to establish dominance, then a clear line begins to inch along Carter's road.

"He's heading that way," she says. "Give it a couple of hours, should have him pinpointed."

Sam looks up, frowning. "A couple of hours?"

"It's not instantaneous. Besides, what's the point in tracking him while he's on the move? Let him settle somewhere he thinks he's safe."

"I could start tracking him him with GPS and traffic cameras in that time."

"Do it, then." She fixes him with a glare. "I do things my way; you're entitled to do them yours. But that doesn't involve me and I'm not about to argue over it."

Sam grits his teeth. Every second that ticks by is a second that Dean gets further away, and Sam isn't about to sit and twiddle his thumbs when he could already be searching. He especially isn't about to start taking orders from her. "Fine," he growls, then turns and strides for the door. He only hesitates when he realises he isn't being followed. There's a pause, and Sam glances back. "Cas?"

The angel looks uncomfortable. Apologetic. "Sam, my grace," he tries to explain. "I think I should wait with Dr Carter. I'd only slow you down."

Frustration tugs on Sam's fingers and makes his fists clench. He wants to argue, except he remembers last time all too well. Cas without his grace, though it pains Sam to admit it, is more a hindrance than a help. "Alright," he sighs, and doesn't miss the way Cas bows his head in shame. "I guess we'll see which of us find him first, then."

"If you're gonna jack a car, leave the Jeep," he hears Carter call out after him when he's back in the corridor. "It's mine."

If it didn't appear that, in some way, she's still trying to help, Sam's sure he'd make a point of taking it.

* * *

Carter pours herself another drink after Sam's gone. Vodka this time, one shot of Stolichnaya in the bottom of a glass before she decides to go straight to the bottle and necks it. Cas gets offered some as a seeming afterthought, the bottle thrust half-heartedly in his direction, and he turns it down with a shake of his head and a look of distaste.

Carter shrugs. "Suit yourself."

On the table, the line of goop, glowing like a filament, continues to inch further along the map. Cas steps closer, brow furrowing as he studies it. "Is this in real time?"

"Nope. Waiting for it to catch up."

She's back to leaning casually against the countertop again, though there's still a disgruntled frown on her face that says she's feeling the stress as much as he is. Well, not that much. Most likely not even close.

Cas straightens up again to fix her with a stare. His head tilts to one side, watching her bring the bottle to her lips again as the muscles in her throat work to swallow. There's a beat before she seems to notice and aims that ever-present glare in his direction. "What? Got something on my face?"

"You're unhappy about failing." He says it bluntly. Perhaps it should have occurred to him to have more tact, but from her reaction, the observation is accurate.

She pouts, drinks again. "Wouldn't anyone be?"

"Perhaps. But why, exactly, did you care to help Dean at all? He's a hunter. You've allied yourself with demons. Everything says he should be your enemy."

Carter shrugs. "He offered to pay."

"Is the loss of income really so distressing for you?"

"No. I fucked up a surgery I'm supposed to be good at. Bruised ego, I guess."

Cas isn't sure how much he believes that.

Carter finishes what's left in the bottle with a final gulp before tossing it onto the side and heading for another of the cupboards. This time she pulls out what looks like a steel briefcase from somewhere close to the floor before setting it down beside the used beakers on the countertop and flipping open the clasps. The top gets lifted up and propped open, allowing Cas to see the plastic placeholders inside making space for three syringes and accompanying vials of medication and hypodermic needles, situated below panels of blue insulating material in the lid. What she intends to fill it with, Cas figures the next few seconds will eliminate the need to guess.

It's entirely expected when she goes for the fridge as her next target, pulling out several vials of clear liquid and inspecting the labels. "I presume you aren't debating how best to treat Dean with some combination of saline and sugar solutions?" Cas prompts.

Carter chooses one of the bottles then sets the others back inside the fridge door, before reaching for a conical flask from beside the sink and setting both containers down beside each other. "When we're dealing with an uber-powerful demon, it's gonna take more than a bog standard sedative to bring him down."

He watches her throw open yet another cabinet to reveal rows of bottles and flasks, many of them with peeling yellow labels that he suspects must be over half a century old. Carter plucks more ingredients from the array of bases and reagents and starts mixing.

He eyes her cautiously. "Just how powerful of a sedative are we talking about?"

"Something powerful enough I'm sure it would knock even your socks off."

A frown creases his brow. "A sedative, no matter how powerful, shouldn't possess explosive capabilities."

"No, it's…" Carter rolls her eyes in exasperation. "I'm being figurative. Could you pass the nitroglycerin?"

She jerks her head in the direction of the shelf beside his right shoulder. Cas turns to it, scanning the array of evidently stolen medicine bottles with an eyebrow raised. "Figurative?" he challenges as he selects the relevant bottle and holds it out to her. "Yet you want nitroglycerin."

"It's good for treating heart conditions," she retorts. "Thought he could use some of that."

The concoction is surprisingly unreactive as she continues to mix, exhibiting no bubbling or hissing or puffs of smoke. By the time Carter finishes up and reaches for a syringe to draw it into a vial, the liquid is still thin, watery and crystal clear.

"Ought to do it," Carter murmurs, measuring out a dose and depositing it into the carry case. When she returns to the fridge, it draws a raised eyebrow from Cas.

"So, you've clearly anticipated the need to sedate Dean," he remarks, watching her draw a tube ready-filled with an inky black substance from the top shelf, then set it down in the second slot. There's a label attached where Cas can just about make out a handwritten scrawl. In normal circumstances he'd be able to read it without issue even at 500 yards, but with his grace waning, everything is fuzzy. "And what exactly do you intend to do to him with that one?"

Carter chuckles, a wry smile spreading over her face as she equips a needle than snaps the case shut. "Nothing. That one's for me."

"Oh?" He raises an eyebrow.

"I've fought Dean once before. Back then he was human, and already difficult enough to overpower with that thing on his arm. This should put us on more even footing."

That throws Cas for a loop. "You've fought Dean?"

"He didn't tell you? Son of a bitch came at me with my own scalpel. Didn't exactly leave me much choice."

Dean hadn't told him. It makes Cas' stomach churn uncomfortably as he wonders what else his friend had been hiding. "So what is it?"

"The alchemical term is Azoth. Also known as…"

"The Ultimate Cure." He interrupts her, and gets a look of both annoyance and surprise.

"When did you become an alchemist?"

"I'm an angel. I was there when humans first discovered alchemy."

"Huh." A disgruntled look crosses her face. "Perhaps you could tell me the perfect recipe then. I've only spent decades trying to find it."

"I'm afraid I don't know. I believe that was something my father intended for humankind to discover for itself."

Carter scoffs. "I think humankind dropped the ball on that front. These days I feel like I'm going at it solo." Irritated, she returns her attention to watching the spell at work atop the table.

A few seconds pass in silence, both of them lost in thought. From everything Cas has seen of the past few centuries, he supposes she isn't far from the truth. Alchemy is a dying art. Arguably, for good reason. Cas has seen the vacant spots in Heaven once meant to be occupied by Edward Kelly and John Dee, but right now, he really can't bring himself to care too deeply about the fate of Carter's soul.

"Can it be used to cure Dean?" he eventually asks, drawing her attention again and prompting the return of the characteristic scowl.

"Doesn't work like that. Being a demon isn't a disease."

"After everything you must have seen of demons, you truly believe that?"

Indifferent as ever, Carter only shrugs. "It's not an illness. It doesn't compromise the body's ability to function; decrease its efficiency in any way. It's just a change of state. A demon isn't a diseased human any more than ice is diseased water. It's just a different way of existing."

"I'm sure Dean would beg to differ."

"Well, he can differ once we've found him." Carter reaches for the bottle of vodka on the side, then remembers that she finished it and instead goes for the kettle. "Fuck it, I'm making tea."

Again, she only seems to offer him some as an afterthought, grabbing a mug and waving it vaguely towards him. He turns it down, eyes fixed on the orange line crawling over the map atop the island instead.

"They say Azoth in its true form is the cure to death itself," he muses aloud, not really paying attention as she busies herself.

"Supposedly. Though, if I've not distilled the true form yet, I doubt anyone has."

There's one pertinent question he still hasn't asked. "What use do you have for Azoth?"

"Are you seriously asking what use I have for the ultimate cure to any ailment?" Her tone is biting. Defensive.

Cas' eyes narrow. There's clearly a lot she isn't telling him, yet even now, he doesn't get the sense she's untrustworthy. Not truly. Her desire to help Dean, at the very least, seems genuine. "Forgive my curiosity. I've learned a great deal about humanity since I encountered the Winchesters, but you're the first human I've met who seems to be able to strike deals with demons on equal footing. Add to that, you appear to have achieved one of the great goals of alchemy and admit to having the intent to use the product on yourself. Yet, despite being a doctor, it would also appear you have no intent to use it on anyone else. I do have questions."

"I'd say you have too many." She keeps her back to him as she pours the tea, shoulders hunched.

He asks the next question abruptly, drawing a scowl as she finally turns and fixes her gaze on him, eyes hard. "How old are you?"

"And there's another one."

Cas isn't backing down. "Older than you look." It's said as a statement, not a question.

Carter huffs, looking like she's about to retaliate further, but then realises he has her. No point trying to evade it now. "I'm 91."

Somehow, Cas doubts even Dean knew that. "Then I'd say your formula has been...effective."

Carter sips at her tea, hiding her face in the mug. "I used that stuff to bring myself back from death's door. Been trying to tweak the formula ever since so one day I won't have to keep topping it up just avoid regressing into the state of 'dying from radiation sickness'. Not there yet, but I've got a few tricks up my sleeve."

"Tricks such as what you put in that box?"

She stops mumbling into the mug just enough that he can see her grin. "That particular variant has an incredibly high potency matched only by the shortness of its half life. It wears off fast. I take that, it'll ramp me up to a state where I could probably take on the Devil himself without breaking a sweat, but it only gives me a window of about half an hour to bring Dean in."

"What if you miss the window?"

"I won't."

"You seem very confident."

"Well, if I do, I have neither the means nor the inclination to gather the ingredients to make more, so it isn't really an option. I don't intend to fuck up twice in one day." It's said in a tone of bitter self-deprecation, but it further stokes Cas' curiosity. Even for an angel, alchemy is a mysterious field.

"And what exactly is the process for distilling Azoth?"

She ignores him, looking instead at the map. "Huh." Her eyebrow raises as she sips again at her tea.

It's obvious she's avoiding the question, but as Cas follows her gaze, he very quickly finds he doesn't care. The fluid has ceased creeping like molten lava over the paper, and instead has solidified into what looks more like a black, glassy pebble resting atop the map somewhere in the region of downtown.

"Would you look at that," Carter says. "We've got him."


	5. IV

There's CCTV in the parking lot. If that's the universe trying to make up for the general shittiness of today with one stroke of luck, Sam will take it. He has the oddly, but fortunately, unmanned security office broken into in minutes and runs through the camera feeds to find out which way Dean went. The Impala is hard to miss: it turned left out of the exit ramp about fifteen minutes ago, taking Dean north. Granted, it isn't much, but it is a start. Sam wipes the past six hours of footage from the drive and gives chase in a stolen Ford Mondeo.

It takes some time of piggybacking on the wifi in a Starbucks parking lot hacking the traffic cameras before he finds it: the Impala's distinctive shape taking a route east towards downtown. From there, the trail is easier to follow. He makes the jumps from camera to camera, scribbling down the route on a tourist map snatched from Carter's kitchen. Dean seems to go back on himself, driving the same block several times as if trying to throw Sam off the scent, but three hours and a few more hacks later, Sam's parked up next to the familiar black car at the end of an alleyway, staring down towards where blinking neon lights signpost the entrance to a strip club.

The sky's turned from dusky grey to pitch black in the time it's taken, but Dean hadn't gotten far. Sam feels the unease building in his gut as he ponders that it seemed almost too easy. The hard part will be what comes next.

Mouth dry, Sam gets out and crosses to the Impala, peering through the front window for any sign of what had happened. Even in the dimness, he can see there's blood on the sheets. The sight makes him swallow nervously, the memory of Dean's gaping chest flashing through his head. Dean had been naked when he left. Well, naked except for a flimsy, bloodsoaked gown. Sam wonders if he'd managed to dress with clothes from the trunk, then remembers Dean's duffle is still on the floor in Carter's apartment.

If he'd gone out looking like that, it would be sure to cause a stir. Perhaps Dean isn't in the strip club after all. Maybe he's parked up, hijacked another car, then left. And there goes Sam's chance of finding his brother.

Sam grits his teeth, praying that isn't the case. He knows Dean would never just abandon the Impala, but there's a part of him that knows just as well that the demon would.

He crosses round to the trunk and pops it open, searching through the arsenal inside. Ruby's knife is also still back at Carter's apartment, he curses, but what he's really looking for is still there: handcuffs engraved with demon trap sigils. So is the holy water. Dean hasn't touched it. A glance up at the devil's trap painted under the hood, Sam wonders if he even can.

Deciding he has nothing to lose, Sam takes the items and heads for the entrance.

The front of the club is secluded, a short flight of steps leading down into a basement, and would be easy to miss completely in the absence of neon signs proclaiming "topless girls" or illustrating that point in crude lineart. Weirdly, there's no doorman. As far as he can tell, the place isn't closed, yet Sam can just walk straight in with neither money nor ID. It strikes him as just as off as the missing security guard back at the apartment complex.

An electronic bassline thumps faintly from somewhere underground as he draws closer. The scent of weed drifts out to meet him, mingling with the stink of garbage from some nearby dumpsters, and Sam wrinkles his nose. As seedy goes, this is scraping the barrel.

He takes the flight of steps and enters through a half-open door.

* * *

 _Two hours earlier_

Dean pulls up at the end of the alley, hits a pothole, swears, then turns off the engine. It's pitch black outside, though even without any means to tell the time, he can sense the night's still young. He's buried himself in the seediest part of the city he could find, hoping it's enough to throw Sam off the scent before he bails out of town completely, and it suits him just fine. A leering grin creeps over his face as he spies the flashing neon signs in the darkened space between two buildings. If it weren't for the blackness making the obnoxious glare stand out, he'd have missed it. Dean can't help but chuckle as he imagines Sam's reaction to this place. Even for a strip joint, the location is sketchy, and he isn't 100% sure the place isn't a brothel putting on a front, but hell, either way is fine by him.

Part of him still wonders if he should have just bolted for the interstate right away. If he wants to lose Sam, it would seem like the quickest way to do it, but then, that's exactly what his brother would expect. As it is, his chest is still dripping blood. It had only taken minutes since he'd left Carter's apartment for the shakes to start, then the breathlessness, stabbing pains as his body fights to repair itself. An intercity drive tonight doesn't seem like the best of ideas.

Or maybe that's just an excuse. If he's being honest, and that isn't exactly a trait common to demons, he's half hoping Sam will show up. His fingers flex on the steering wheel, twitching with the memory of a hammer's weight and unfinished business. Hiding from Sam is what he did last time. Back then he was weaker, still clinging to the human sentiment that he could somehow still protect his brother if only Sam would let him go. This time, he won't be weak. If Sam finds him, Dean will kill him.

And hell, if nothing else, Dean just wants to indulge himself in strippers and booze. Six hours ago, he'd been dead. He deserves a little fun.

Dean gets out of the car, crusted red-black blood coating his chest while the gown hangs limp and filthy around his hips. There's a doorman having a smoke by the entrance, and he does a double take as Dean approaches, eyes popping at the bloody, naked man stepping into the light.

"Whoa, dude," he murmurs, shocked. The cigarette slips from his fingers to the floor. "Are you alright? D...do you need me to call an ambulance?"

Dean advances, revelling in the horror on the man's face. He wonders what's running through the guy's head right now. Bloody, mentally unstable hospital escapee? It seems the most obvious conclusion to jump to. "Ambulance? Nah," Dean says with a smirk.

The doorman is visibly trembling. "Okay, man, just...just let me call for some help…" He's fumbling in his pocket, trying to reach for his cellphone or maybe a radio, but Dean is too fast. A hand grabs the doorman's wrist, forcibly drags him to slam against the wall, then backhands him across the face.

The man stumbles away, spitting blood. "What the fuck?" he gasps, eyes even wider now, afraid. Adrenaline courses through Dean's system. His heart - torn, repaired, reborn - gives a powerful beat.

"You wanna help me, man?" Dean says, grasping at the man's jacket and bending him over to knee him hard in the stomach. "I know just what you can do."

The doorman drops to his knees. Blood and spit dribble from his mouth, trickling to the floor as he tries to scramble away, but Dean grabs the back of his head and tangles his fingers painfully in his hair.

The man never had a chance. Dean wrenches him upwards, spins him, then slams the doorman's face hard into the brick wall. A scream pierces the air, going unanswered as electronic beats thump loudly in the basement down below. Blood pours down the man's face, and when Dean pulls him back to inspect the damage, he sees a clearly broken nose.

Dean goes again, slamming the man's head against the blood smear left behind from before. He hears a crunch, a scrape, and then another quivering scream as the man's hands flail weakly to break Dean's grip. The demon gives a huff of annoyance.

Still having failed to shatter the skull, Dean instead pushes the man's entire body against the wall, an elbow pressed to his back. Then, with both hands gripping the man's head, he twists.

There's a crack, then silence.

Dean steps away, allowing the man's body to fall to the floor. The abandoned cigarette glows faintly beside it. The demon grinds it under his bare heel, and smiles. "You can do just that."

He kneels down to begin stripping the doorman of his clothes. They're not bad: boots, jeans, and a black t-shirt identical to many an outfit Dean's worn. The leather jacket is a little old-fashioned and not quite his size, but it'll do.

He pulls on the clothes and leaves the body in a nearby dumpster, along with the bloody rag that had once been a gown, then Dean adjusts the collar of his jacket, wipes a fleck of blood from his chin, and walks down the steps into the club.

* * *

The bass continues to pound in Sam's ears as he navigates his way through the joint. To say the entrance is so well hidden, it's crowded. Numerous sleazebags lie about on the grimy couches, while topless waitresses deliver trays of drinks to the slightly-less-grimy punters sat around tables. Sam hates how easily he can picture his brother here.

No. Not his brother. Just the demon that now has Dean's face.

Sam makes his way towards the bar, anxiety creeping up on him as he wonders what might happen should he start asking questions, and dreading the answers he'll get. In any other circumstance, flashing a fake FBI badge would normally loosen tongues. Here, he suspects it would only tighten them, if not get him thrown out completely.

The bartender gives him a look as he approaches, and he orders a tequila shot out of politeness. Truth be told, he kinda feels like he could do with one, too.

He stands there for several minutes, eyes darting round as he tries to make out any faces in the dimly lit room, before the bartender notices his attention clearly isn't on the girls. "Looking for someone?"

It's said in a hostile grunt. Sam's starting to worry he genuinely is giving off vibes of 'undercover cop'. "Uh, actually yeah," he says, trying to seem as non-threatening as possible. "A, uh...friend. Tall, brown hair, green eyes. You seen anyone like that?"

The bartender just stares coolly. "I don't pay attention to the color of men's eyes, as a rule. Could you try for anything a little less generic?"

"He…" Sam licks his lips. "He wasn't really wearing much, last I saw him?"

There's an awkward beat. The bartender stares. "You got the wrong club," he says. "Girls only here."

"No, I…" Sam sighs, grimaces slightly, but he's spared having to explain by a sudden commotion going off off to his left. He glances over to where a couple of bouncers are facing off with a man down by the front of the stage. It seems that a punter has gotten a little too hands-on with one the girls.

Sam's about to ignore it and make an attempt at asking again, when the punter in question turns. Blue and pink lights flash over the profile of his face and Sam's stomach flips over. "Dean?" It's whispered more to himself in shock than anything else.

The bartender gives him a dirty look, then goes back to pouring drinks as Sam starts to make his way over towards his brother. He'd half been hoping Carter was right and she'd find Dean first, if only it meant he didn't have to see his brother like this. "Dean, what the hell?"

His shout is enough to grab Dean's attention even over the music. The demon turns his back on the bouncers, throwing open his arms as he sees Sam. Clearly, he's gotten clothes from somewhere, and there's an open liquor bottle clutched in his right hand. "Sammy!" he bellows, drunk. "Wondered if you'd find me. Actually, I was kinda hoping for it."

Sam just gives him a stony look. "Yeah, well, here I am. And now it's time for you to come with me."

"Aw, come on, Sammy. Don't spoil the fun. Place is open for hours yet."

Behind him, a bouncer grabs Dean by the shoulder and gives him a shove. Dean turns back with a glower to find a meaty finger being jabbed in his face. "Last warning," the bouncer growls. "Keep your distance, hands off, and no more comments like that, or you're out." He glances over Dean's shoulder and shoots Sam a suspicious glare. "That goes for you too."

Dean rolls his eyes. "You don't have to worry about him, he's a total prude," he says, staggering awkwardly in Sam's general direction. "Aren't you, Sammy?"

It's punctuated with a hiccup, and Sam can't help but think how utterly pathetic it is. "Dean," he hisses. "Carter has a way to fix you. Please, I know this isn't you. Deep down, you're still my brother. Just come with me and we can sort this."

Dean's eyes turn cold. "Why the fuck would I do that, Sammy? You know I don't want to be cured."

"Dean…"

"I like it here, Sam. Think I wanna stay. You want me to come with you, well...you're gonna have to make me."

Sam's jaw clenches and he draws in a breath. He knew this wasn't gonna be easy. "Not here. Come upstairs, and if you really wanna fight, we'll have it out there."

"What's wrong with here?"

"There's...Dean, there's people…"

"Fuck them." The brutality with which he says it is shocking. Dean takes a step towards his brother, a predatory glint in his eyes. "You think I care if they get hurt? If they see what I really am?"

Behind him, the security guards have sensed trouble again. The same one as earlier, beefier than his colleague, strides up, a firm hand closing around Dean's bicep. "Alright, that's enough. Your buddy's right. You two wanna fight, you can take it outside..." He starts to drag Dean roughly towards the door, while the second one takes an imposing step towards Sam.

Sam isn't even looking. He reads Dean's intent on his face a second before it happens. Not enough time to stop him.

Dean's eyes flash black, and he turns. The bottle comes up, shattering over the bouncer's head and making him cry out as he clutches a hand to his skull. Blood seeps between his fingers. There's cries and movement around them as people scramble to get away from the soon-to-be fight, but for the most part, many are still content to watch from a distance. On the stage, the girls keep dancing, though one of them clad in green and gold falters. Her eyes glance nervously towards Dean.

The second guard roars. He charges Dean, ramming his shoulder into him with the intent of knocking him to the floor, but with more co-ordination than any drunk person should rightly have, Dean fluidly side steps out of the way. The shattered bottle is still in his hand.

He swings again, bottle clutched by the neck, and brings the jagged glass end to slash over the guard's throat. Arterial blood sprays. The bouncer clutches at his throat and falls to his knees, while Dean looks up and surveys the crowd with cruel, black eyes.

That's when the perturbed cries turn to outright screams.


	6. V

Carter parks the Jeep several metres from where they find the Impala at the entrance to a darkened alleyway, ensuring she keeps sight of it in her rearview mirror as they roll to a stop at the roadside.

On the passenger side of the car, Cas twists in his seat to get a better look. He bites his lip, uncertainty creasing his brow when he spies the signs for the club. "You think he's down there?"

"It's what the map says," Carter affirms, glancing at the folded sheet still featuring the black blob on the dashboard. "Men like strippers. Don't go clutching your pearls."

"No, it's…" Cas gives a scowl. "I'm not shocked by a demon finding a den of iniquity. It's just that this is…" He trails off, pulling a face.

"Kind of extreme?"

"Yes."

Carter quirks an eyebrow. "You should have seen the strip joints in East Berlin." She leans over him to reach for the metal case she's left in his footwell, the sets it on her lap and pops the clasps. The syringe for Dean she takes out first, slipping it inside her jacket, then turns her attention to the black needle meant for her.

"I need to ask a favor," she says seriously, lifting the top tray so that Cas can see the array of vials and a tourniquet laid out underneath. They're filled with the same black substance as in the syringe. Or maybe not the same.

"Go on."

"If I crash before we manage to get Dean back to my apartment, I need you to boost me. These are the standard doses. Less potent. Take any of them, doesn't matter which, slot it in a syringe and jab it in a vein. Should keep me going long enough to fix him."

"How likely is it that you'll crash?"

"Depends how nice Dean wants to play." She takes out the tourniquet and pushes the top tray down again, then slides her left arm out of her jacket and secures the strap around her bicep. He watches as she holds her breath, clenching a fist and bending her arm a few times, though best as Cas can tell, the veins are becoming no more visible. "This stuff can fuck with your head," Carter says after a beat, seeming almost as an afterthought. "Times I've been on it before, I've gone fucking crazy. So if you see me start to do anything unusual, if it seems unnecessary or extreme…"

"Try to stop you?"

"No." Carter looks up at him. "Best to stay the fuck out of my way."

Without further warning, she aims the black-filled syringe at her arm and stabs it in. The plunger depresses, and the black formula seeps into her bloodstream. A sigh slips past her lips.

Cas watches, eyes widening as he sees the blackness beginning to creep visibly along her veins, her eyelids fluttering closed, then she spasms. Her jaw clenches, tendons in her neck popping out as her hands curl into claws and every muscle in her body seems to tense. Then, it passes. Her eyes open, and to Cas' unease, the irises seem to have turned black.

"...Dr Carter?"

For a moment, she doesn't respond. Cas leans a little closer, curiosity and apprehension mingling in his gut as he tries to get a better look. Then, she smiles.

Perhaps it's more of a leer, the corners of her lips twitching and then turning up in a way that doesn't quite seem natural. The expression on her face is thoroughly unsettling.

Cas clears his throat. "Are you, uh...are you alright?"

"I'm great," she answers, and her voice sounds different. Sharper. More resonant. When she moves again, closing the case and setting it on the back seat, her movements seem almost inhuman in their speed and fluidity.

Carter slips her arm back into her sleeve and adjusts her jacket. She blinks a few times, and when she's done, he thinks her eyes look just slightly less unearthly than before.

She reaches across him again to get the glove compartment, and mild surprise sweeps over him when she takes out a set of steel knuckle dusters. There are pointed studs on the outer edge.

"Do you intend to use those on Dean?" he asks, apprehension in his voice.

"But of course." Her chilling smile widens as she slips her fingers through the holes, then turns to him. "Let's go get your boy."

* * *

There's a maddened stampede as people begin to rush for the door. One would-be hero tries to jump Dean from behind, but just gets an elbow to the face and a bloodied nose for his efforts. It would turn bloodier still if Sam didn't grab him by the shoulder and shove him towards the exit. Stumbling off, he seems happy to take the unspoken advice.

"Alright, if this is how we're gonna do it…" Sam says, slipping a hand inside his jacket to take out the cuffs.

Dean laughs when he sees them. "What? One-on-one, you and me? Didn't you learn your lesson last time?"

They're squaring off to fight when they're interrupted by the sound of gunshots. Dean gives a grunt, then Sam sees the fresh blood beginning to pour from his shoulder. Pain doesn't register on his face. He only looks pissed.

Dean turns, eyes darting around the quickly emptying club for whichever hero decided to bring out the firearm, and Sam takes advantage of his distraction to rush him. He has no expectation of actually overpowering him, but if he at least gets Dean's arms in the right position, he might actually have a shot at getting the cuffs on.

Sam's upper body slams into Dean's. The demon rolls with the momentum, manually throwing Sam off in a move that would have sent him crashing to the floor, if Dean hadn't thrown out his arm at the last second and jerked his wrist so that Sam hurtles towards the wall instead. The demon's hand rises in front of his face, fist closing, and Sam feels the air being squeezed from his lungs. His feet don't touch the floor.

Another gunshot comes. This time, Dean staggers back as the bullet tears through him, punching through his sternum, through Carter's meticulous work on his heart, then exits his back in a plume of red to blast a hole straight through his chest.

The pressure on Sam's lungs lifts and he falls to the floor. Immediately his head jerks up, panic gripping as he wonders if that's truly game over. He needn't have worried.

By now, the club is practically empty, tables upturned by the stampede and floor sticky with spilled drinks. The music has gone dead.

Dean, however, is still standing.

Curious, the demon tilts his head down to stare at his own chest. He reaches for the hem of his black t-shirt then lifts it to his collarbone, studying the skin beneath the mingling layer of fresh and dried blood. There's a hole, small, neat, slightly to the left of the straight pink line left by the incision. And before his eyes, it's closing up.

The redness recedes, the wound puckering, narrowing, and within seconds it's nothing but a faint blemish on his skin. Dean grins.

His head snaps up, crazed smile fixed in place as his eyes hone in on the direction the shot had come from. Still standing there, gun gripped in trembling hands and disbelieving horror on her face, is the shooter.

It's one of the strippers, still clad in a green and gold bikini decorated with feathers, holding the gun she probably bought to defend herself from the predators that might try to follow her home into the night. Against a monster like him, it will do her no good.

Dean's eyes fix on her, and in that instant she comes to her senses. The gun falls from her hands and she runs.

Sam cries out, an indistinct noise meaning only for Dean to stop, but it's too late. The demon throws out a hand, halting the woman mid-stride as she finds herself suspended in the air and lets out a scream. Then Dean snaps his fingers.

Instantly, her head spins through 180 degrees with a snap, then her body falls to the floor.

Sam roars. He can't keep it contained, the horror bubbling inside him as he tries so hard to focus on the voice in his head telling him " _it's not Dean it's not Dean_." His own screaming almost seems to drown it out.

Unaffected, the demon crouches down to pick up the shattered liquor bottle dropped at his feet, then begins to calmly pace towards Sam. Sam's hands scramble inside his jacket for the bottles of holy water, frantically getting the lid off one just in time to throw the contents over Dean's face.

It provokes a hiss of annoyance, but nothing else. Dean's fingers close tight around Sam's neck, then once again he's pinned up against the wall.

* * *

"Wait." Carter throws an arm out to stop Cas as they approach the doorway.

The pair of them halt, and Cas strains for a moment to listen. Hearing nothing unusual, he tilts his head. "What's wrong?"

"No doorman."

"Is that unusual?"

"Yes." With a frown, she takes a step towards the entrance and reaches out a hand to the wall beside the door. There's a dark red stain on the brick. Her fingers brush the substance, shining and glossy in the neon glow, then come away slick with red. They both know what it means.

Cas goes still, his deteriorating senses straining to detect something. "Smell that?" he says after a moment.

Carter looks back over her shoulder at him. "I don't have a sense of smell. Lost it a long time ago."

"There's something…" He sniffs the air again. "Rotting."

Her eyes follow where his gaze is currently pointing. "That's the garbage bins."

"No." Cas strides over to the dumpsters, the feeling of dread in the pit of his stomach growing by the second. "Something else."

He reaches up to grasp the top of the nearest bin, and before Carter can protest tilts it so that the whole thing pivots onto its side. The lid tips open, and among the rancid black garbage bags that spill out, a naked body tumbles onto the concrete. Its face is a mangled mess, blood matting its hair.

Neither of them flinch, but both look up to share a knowing glance. Cas licks his lips. Before he can say anything, from somewhere underground, they hear a scream.

* * *

Dean's grip tightens around his brother's throat. Sam's eyes bulge, flitting to the shattered liquor bottle gripped in the demon's hand, drawing closer to his face. His fingers claw at the death grip crushing his windpipe, struggling, mouth open in a silent gasp for air, but it's no use. He can see Dean's intent written plain on his face, and it chills Sam to the core.

Dean snarls. He leans in, eyes flooding black as hatred pours from his gaze. "I may not have the Blade," he hisses in a voice like ice, "But don't think that will stop me. I'm gonna kill you, then I'm gonna kill Cas, and if the bitch gets in my way I'll kill her too. And after that, I'm gonna head out into the world with free reign to fuck, kill, and torture whoever I please, and I'm not gonna think about you at all."

The edges of Sam's vision are turning black. He can feel his heart pounding, horror and anguish wrenching at his chest right alongside it, as if trying to fill the vacuum in his lungs. The image of black, hate-filled eyes lingers stark in his mind long after everything else has begun to fade.

From somewhere not far behind Dean, a chuckle sounds. "Kill me?" The voice is cold. Chilling even moreso than usual, and higher, with a strange, unsettling resonance like a metallic ring. "You could make a mountain from the bodies of the men who've tried."

Dean glances back over his shoulder. Carter stands there among the debris of the club, statue still, her lips pulled up in a disconcerting grin. In her left hand is a set of studded knuckle dusters, fingers flexing on the heavy steel. Her eyes are almost as black as his. The pupils are blown wide, almost to the edges of the iris, and the veins have turned dark.

Slowly, her head tilts forward. Before Sam blacks out, he sees the veins on the side of her neck, inky black lines beneath chalky skin.

A growl rumbles in Dean's throat. Carter steps forward, and he twists away from Sam and swings. The shattered bottle arcs towards her face, sharpened edges inches from her skull when her hand comes up and stops it with an iron grip on his wrist. It's like he's swung a punch at a brick wall.

Taken by surprise, Dean finally lets go of Sam. The younger Winchester crumples to the floor, barely conscious, and the demon turns to face his rival. She tries to twist his wrist, wrenching it hard towards her chest, and he breaks her grip with a grunt. It's harder than anticipated.

Dean's lips curl into a snarl. "Somebody's been playing with the bathsalts."

That demented smile on her face widens. "Oh, but how else would we have fun?"

He throws a punch again, and she blocks it, knocking his hand to the side with a crunch of the knuckles against his wrist. Then she grabs him by the throat.

There's a moment as she pulls him closer to her, faces inches apart as black eyes stare into black, then she throws him with shocking strength across the room. His back collides hard with the wall.

Dean grunts, shakes his head to clear it as he picks himself up. His hands ball into fists, makeshift weapon gone, but he tells himself he doesn't need it.

Carter advances, purpose in her stride as she closes in. Unlike Sam, she seems neither scared nor concerned for his wellbeing at all. "You could come with me quietly," she taunts, "Though, I'd really rather you didn't."

Her elbow jerks back, ready to throw a punch, and Dean thrusts out his hand. Instead of flying across the room as he'd expected, Carter only flinches and halts. "I'd been wondering if that would work," she laughs. "Apparently not." In an instant she's striding forward again, then Dean feels studded steel connect with his jaw.

Blood sprays from his mouth to the floor, and Carter gives a twisted, sadistic laugh. Dean growls, turning his gaze back onto her with murder in his black eyes. For the second time, they fight.


End file.
